I think .004 is neglible, especially for pistol plinking ammo, and probably due to the bullet tips not all being exactly the same shape. It's likely not caused by the die unless you don't have the lock ring snugged down tight enough.

Check how much flare your using, if your still on the upswing of the stroke after the disk is aligned with the powder drop opening in the powder measure body, you may be putting too much flare in your case.

Iíve found that if you chamfer the I.D. of cases and flare just enough for bullet alignment, you minimize COL when using the AutoDisk.

Also using mixed brass can add to COL variation due to how hard/soft each case is.

My lee 9mm die is more consistent then a Redding Comp Die with my lead bullets. Down to .001" good. If your getting that must variation it's probably not the die. But first just to be safe you need to put the seating stem in a drill to spin it and polish it up a little with some 400 grit wet dry paper.

Besides that you have a good amount of variation in a lot of presses. Even my 550 would do it if I didn't have a full shellplate for instance. But if I did everything the same when I load in batchs I almost had zero variation.

.004 variance is negligable for plinking rounds, and as stated earlier it is probably due to bullet manufacturing variances. It could also be due to a poor fit between your seating plug and the bullet profile - that could be fixed but is not worth the trouble for plinkng rounds. I've also seen COL variances using match grade bullets from Sierra, but not with Hornady. So, that in itself would rule out the Lee die.

Lee dies are good. Don't let someone steer you wrong.

If manufacturers were keen enough to box up their product from a single machine instead of from multiple machines, the tolerances we reloaders would find would be kept much closer.

.004 variance is negligable for plinking rounds, and as stated earlier it is probably due to bullet manufacturing variances. It could also be due to a poor fit between your seating plug and the bullet profile - that could be fixed but is not worth the trouble for plinkng rounds. I've also seen COL variances using match grade bullets from Sierra, but not with Hornady. So, that in itself would rule out the Lee die.

Lee dies are good. Don't let someone steer you wrong.

If manufacturers were keen enough to box up their product from a single machine instead of from multiple machines, the tolerances we reloaders would find would be kept much closer.

THis ^. Th variation means nothing accuracy or pressure wise. When yo uget to .050", start worring. As noted, the bullet noses/tips will vary from run to run, Boring a dead center hoel in the Lee seating stem allows the bullet to deat on the ogive, much better bullet fit & closer tolerances.

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"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".

Whether the bullet is seated using the nose or the ogive it is still a matter of pressing the bullet into the case. Different brands of cases have different wall thicknesses and volumes meaning there is different pressure trying to force the bullet out of the case between the seating and crimping. To minimize OAL differences use one brand of case and take the same amount of time doing each step of the operation.